1. Field of the Invention
This invention relates to improvements in a steering lock system for locking a steering mechanism, and more particularly to a steering lock system which operates only when a vehicle is in a parking condition.
2. Description of the Prior Art
Automotive vehicles are usually equipped with a steering lock system which is operated to lock a steering shaft of a steering mechanism when an ignition key is pulled out of a key cylinder after the key cylinder is rotated from an ACC (accessory) position to a LOCK (locking) position with an ignition key, thereby preventing the vehicle from burglary. In general, the key cylinder has an OFF position for switching OFF an electric system of the vehicle, positioned between the LOCK position and the ACC position. The ACC position is followed by an ON position for switching ON the ignition system of an engine and a START position for operating a starter motor and the like.
Such a steering lock system is arranged such that the ignition key is disabled from being pulled out of the key cylinder at the positions other than the LOCK position. However, if the key cylinder is carelessly rotated from the ACC position to the LOCK position, the ignition key may be pulled out of the key cylinder, which is not desirable from the viewpoint of safety.
In view of this, it has been proposed that the key cylinder is once restrained from rotation toward the LOCK position when the key cylinder comes from the ACC position to the OFF position; and the key cylinder cannot be rotated to the LOCK position unless such restraint is canceled upon operating a cancellation button, thus attaining safety. Such an arrangement is disclosed, for example, in Japanese Patent Provisional Publication No. 57-164841.
However, the above manner of cancellation is unreliable and troublesome, and therefore an improved cancellation arrangement is desirable.